Synnefo

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from django.db.models import Manager

from django.db.models.query import QuerySet

class ProtectedDeleteManager(Manager):

    """Manager for protecting Backend deletion.

    Call Backend delete() method in order to prevent deletion

    of Backends that host non-deleted VirtualMachines.

    """

    def get_query_set(self):

        return BackendQuerySet(self.model, using=self._db)

class BackendQuerySet(QuerySet):

    def delete(self):

        for backend in self._clone():

            backend.delete()

from django.db import IntegrityError

from synnefo.db.managers import ProtectedDeleteManager

    # Custom object manager to protect from cascade delete

    objects = ProtectedDeleteManager()

    def delete(self, *args, **kwargs):

        # Integrity Error if non-deleted VMs are associated with Backend

        if self.virtual_machines.filter(deleted=False).count():

            raise IntegrityError("Non-deleted virtual machines are associated "

                                 "with backend: %s" % self)

        else:

            # ON_DELETE = SET NULL

            for vm in self.virtual_machines.all():

                vm.backend = None

                vm.save()

            self.virtual_machines.all().backend = None

            # Remove BackendNetworks of this Backend.

            # Do not use networks.all().delete(), since delete() method of

            # BackendNetwork will not be called!

            for net in self.networks.all():

                net.delete()

            super(Backend, self).delete(*args, **kwargs)

                                related_name="virtual_machines",)

    backend = models.ForeignKey(Backend, related_name='networks')

    def test_delete_backend(self):

        vm = mfact.VirtualMachineFactory(backend=self.backend, deleted=True)

        bnet = mfact.BackendNetworkFactory(backend=self.backend)

        self.backend.delete()

        self.assertRaises(Backend.DoesNotExist, Backend.objects.get,

                          id=self.backend.id)

        # Test that VM is not deleted

        vm2 = VirtualMachine.objects.get(id=vm.id)

        self.assertEqual(vm2.backend, None)

        # Test tha backend networks are deleted, but not the network

        self.assertRaises(BackendNetwork.DoesNotExist,

                          BackendNetwork.objects.get, id=bnet.id)

        Network.objects.get(id=bnet.network.id)

        mfact.VirtualMachineFactory(backend=self.backend)

        self.assertRaises(IntegrityError, self.backend.delete, ())

from synnefo.db.models import VirtualMachine, BackendNetwork

class Command(BaseCommand):

    can_import_settings = True

    help = "Remove a backend from the Database. Backend should be set\n" \

           "to drained before trying to remove it, in order to avoid the\n" \

           "allocation of a new instances in this Backend.\n\n" \

           "Removal of a backend will fail if the backend hosts any\n" \

           "non-deleted instances."

    output_transaction = True  # The management command runs inside

                               # an SQL transaction

        write('Trying to remove backend: %s\n' % backend.clustername)

        vms_in_backend = VirtualMachine.objects.filter(backend=backend,

                                                       deleted=False)

        if vms_in_backend:

        networks = BackendNetwork.objects.filter(backend=backend,

                                                 deleted=False)

        networks = [net.network.backend_id for net in networks]

        backend.delete()

        write('Successfully removed backend.\n')

            write('Left the following orphans networks in Ganeti:\n')

            write('  ' + '\n  * '.join(networks) + '\n')

            write('Manually remove them.\n')